1. Field of the Invention
The present invention relates generally to integrated circuits, and more particularly, to clock generator circuitry that is capable of generating a stable frequency output under various conditions and a method for producing the stable frequency output.
2. Description of the Related Art
An accurate clock generator is an essential component of an integrated circuit. Although varieties of clock generators are available, such as RC-OSC or Ring-OSC, these clock generators suffer from high frequency drifts when the temperature, the supply voltage, and the production process vary.
To overcome the clock frequency drift problem, external crystals or oscillators have to be used as clock generators in order to supply stable clock frequencies to semiconductor chips. However, external clock generators not only occupy more circuit layout space, but also increase chip production cost.
In view of the foregoing, there is a need for a new clock generator that is capable of generating a stable frequency output under various conditions and is compatible with standard CMOS production process.